Have you checked to see if there are speed taps on the control board and if the motor is connected to the proper one for each call? There are usually four; hi, med-hi, med-lo, lo. It also could be labeled cool and heat.

In cooling mode the fan should be set at highest speed and for heating on med-lo to low unless again, there are air flow issues and the unit trips out of high temperature limit which one way to "fix" that would be to increase the speed during heating.

Has the outdor unit ever been changed and if so is it the correct size for the air handler or is it too small thereby someone lowered the blower motor setting to match the smaller outside condenser?

All possibilities.

Advertisement

Have you checked to see if there are speed taps on the control board and if the motor is connected to the proper one for each call? There are usually four; hi, med-hi, med-lo, lo. It also could be labeled cool and heat.

In cooling mode the fan should be set at highest speed and for heating on med-lo to low unless again, there are air flow issues and the unit trips out of high temperature limit which one way to "fix" that would be to increase the speed during heating.

Has the outdor unit ever been changed and if so is it the correct size for the air handler or is it too small thereby someone lowered the blower motor setting to match the smaller outside condenser?

All possibilities.

According to the techs I had out there the outdoor unit and indoor unit matched. I do not know if anything has been swapped out as I've only had the house a year and it was a bank owned property.

I tried to check the control board before but couldn't figure it out. It wasn't labeled at all so I didn't want to mess anything up. I'll see if I can find some instructions on that though.

How hard is hard? When I had it open it didnt blow any harder than a 20 inch box fan from walmart.

The plenum can only be 3 feet in length? Wow. Mines alot longer than that. See pic here:

That is simply idiotic. That's a commercial step down trunk line design used on big commercial systems.

What you need is a regular residential 3' PLENUM, not a 30' duct board commercial trunk line. And some dampers so you can balance that air meaning turn the air flow down through a few if you want more elsewhere.

__________________
Thanks.

The Following User Says Thank You to Doc Holliday For This Useful Post:

Haha It's pretty much chaos up there but in my parents house which was built in the 90s their system is run the exact same way. Maybe whoever is doing the duct training in VA has been smoking something. I didn't do any of this duct work I'm just trying to fix the hell that has been unleashed already.

Haha It's pretty much chaos up there but in my parents house which was built in the 90s their system is run the exact same way. Maybe whoever is doing the duct training in VA has been smoking something. I didn't do any of this duct work I'm just trying to fix the hell that has been unleashed already.

Let me make sure I understand correctly what i need to have.

3 foot plenum and then flex duct from that plenum to all of my vents?

I guess I should slow my roll a bit. Not sure about other areas of the US, just that down here in Texas you won't find anything remotely close to that, not in residential.

What size system is it? And yes, a regular 3' plenum with main lines running out of it. For the amount of air I'm suspecting you need and to save space on the plenum, probably Y connections meaning you could come out with one 10" which would split down the line into two 8's.

Of course the size do the lines is all specualtion until we know the size requirements of the structure (heat load analysis), what is there right now, the duct sizes (if they are too big/small) and the size in cubic feet of each room so we know what size duct will be required to feed said room.

Just looking at that big old trunk lines is making me cringe, I feel all hot and sticky.

Well I figure Texas is hot as crap in the summer and can get pretty cold in the winter too so you all prolly know what you are talking about and if it works better than the crap I have going on now then I'm all for changing it up.

I have been told it's a 2 ton system.
I have done research on this style of duct system and they call it a Reducecd extended plenum duct system.
Apparently the plenum goes a certain distance then steps down a size as vents are run off of it.

I would love to be able to do a shorter plenum. It would make maneuvering around the attic alot easier.

You have a how to or some diagrams somewhere so I can maybe design a better configuration.

Well I figure Texas is hot as crap in the summer and can get pretty cold in the winter too so you all prolly know what you are talking about and if it works better than the crap I have going on now then I'm all for changing it up.

I have been told it's a 2 ton system.
I have done research on this style of duct system and they call it a Reducecd extended plenum duct system.
Apparently the plenum goes a certain distance then steps down a size as vents are run off of it.

I would love to be able to do a shorter plenum. It would make maneuvering around the attic alot easier.

You have a how to or some diagrams somewhere so I can maybe design a better configuration.

I'll work on all the details of that analysis today.

Im definitely not an AC expert....but wouldnt a 1344sqr ft house need more then a 2 ton system?